The present invention relates to mirror finishing in which electrolytic polishing and abrasive polishing by abrasive matter are combined with each other, thereby to give final mirror touches to the polished surface of the workpiece.
In addition to buffing, electro-polishing has been used for surface finishing of, for example, stainless steel. In the conventional electro-polishing, a workpiece is immersed in an electrolyte bath, while being faced to an electrode. In this method, hydrochloric acid or sulfuric acid is used as electrolyte, in which a current of anode current density of 0.2 to 0.7 A/cm.sup.2 is supplied thereby to finish the surface of workpiece to a mirror polished surface.
The electro-polishing is thus efficient for treating surfaces of relatively small area workpieces. However, there are some technical and economical problems in putting this method to practical use for polishing the inner faces of relatively large area vessels, due to large-scaled power supply and the electrolyte facilities required. In addition, the lack of uniformity in anode current density and low polishing speed due to small anode current density present problems.
It is an object of the present invention to give final lustrous mirror touches of high quality to the polished surface of a workpiece by combining electrolytic polishing with abrasive polishing by abrasive matter.
It is another object of the present invention to provide a mirror finishing method to be applied to, for example, stainless steel, with remarkable effect.
It is a further object of the present invention to simplify operation to one process for improving working efficiency.
It is still another object of the present invention to easily and economically polish large area workpieces, including large-sized vessels.
It is still a further object of the present invention to enable a partial modification work.
Other objects and further scope of applicability of the present invention will become apparent from the description given hereinafter; it should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.